According to the people who produce and sell products that
contain MSG, and their friends at the U.S. Food and Drug Administration
(FDA), there are a few, but only a few, people who will suffer adverse
reactions following ingestion of MSG. Moreover, according to industry and
the FDA, it will take a fairly substantial dose of MSG to cause an adverse
reaction.

At the Truth in Labeling Campaign, we know a different
story.

MSG-sensitivity is a term used by people who react adversely
to "monosodium glutamate" and/or any other ingredient that contains
processed free glutamic acid (MSG).

As used here, an "adverse reaction" is an unpleasant
reaction that can be seen or felt by the affected person or an observer.
Skin rash, nausea, migraine headache, heart irregularities, seizures, and
depression are examples of adverse reactions that have been reported following
ingestion of MSG. Each is a visible or observable reaction. When caused by MSG,
each can be traced back to recent exposure to MSG.

We know that MSG can cause the same reactions as those
caused by drugs that affect the nervous system -- reactions that are called
"side effects" when related to prescription or nonprescription drugs
such as Valium. But we know very little about the mechanisms that
underlie MSG-induced adverse reactions. The fairly recent discovery of
glutamate receptors in many locations outside of the central nervous system
(Gill, S.S., Mueller, R.W., McGuire, P.F., Pulido, O.M. Potential target sites
in peripheral tissues for excitatory neuro
transmission and excitotoxicity. Toxicologic
Pathology 28(2):277-284, 2000) suggests that the readily observable toxic
effects of MSG, referred to as adverse reactions, are facilitated by glutamate
receptors in the mouth, lungs, intestines, and muscle, for example; and that
the fate of ingested MSG is not to come to rest in the plasma as elevated
plasma glutamate and from there to be excreted by the liver. Rather, it would
appear that the fate of ingested MSG is to move with dispatch to any glutamate
receptors available to it; and to create an adverse or toxic reaction if any
one of those peripheral glutamate receptors is weak, crippled, diseased, or
otherwise unhealthy.

Relevant to the toxic effects of MSG on the elderly (whose weakened
blood-brain barriers would be less able to keep excess amounts of MSG from
getting into the brain), there is sound science that suggests that the glutamic
acid in MSG may act as a "slow neurotoxin," not resulting in
observable damage such as dementia until years after the MSG was
ingested. The work of Dr. Peter Spencer is
particularly relevant. Mercury, for example, is a slow neurotoxin
-- manifesting its toxic effects years after being ingested. It is entirely
possible that the concept of a "slow neurotoxin" may be relevant to
the production of human adverse reactions.

Gross obesity, stunted growth, reproductive disorders, learning
disabilities, behavior disorders, and retinal degeneration (possibly leading to
blindness) are not classified as "adverse reactions." When
caused by MSG, their roots lie in the destruction of brain cells, possibly
years before gross obesity, stunted growth,
reproductive disorders, learning disabilities, behavior disorders, and/or
retinal degeneration are first observed. Research confirming that MSG
consumed by laboratory animals causes brain lesions
in the area of the hypothalamus has been replicated many times. Similarly,
researchers have confirmed that when MSG is consumed by infant animals,
neonates, and even fetuses, the brain lesions are followed by neuroendocrine
disorders such as obesity, stunted growth, and reproductive disorders.

On the other hand, research that has claimed to find that MSG is
"safe" has always been seriously flawed; and has always been
financed, directly or indirectly, by the glutamate industry.

A third area of concern encompasses a number of pathological conditions
such as addiction, stroke, epilepsy, brain trauma, multiple sclerosis,
neuropathic pain, AIDS dementia, schizophrenia, anxiety, depression, and
degenerative disorders such as Parkinson's disease, Alzheimer's disease,
Huntington's disease, and amyotrophic lateral sclerosis (ALS). All
are known to be affected by free glutamic acid. Whether ingestion of processed
free glutamic acid (MSG) plays a role in causing or exacerbating these
conditions is not clear. Because glutamic acid is involved in all of
them, this conglomeration of pathological conditions is often referred to as
the glutamate cascade.